Prevalence, Course, and Associated Factors of Pain in the Temporomandibular Joint in Early Rheumatoid Arthritis: Results of a Longitudinal Cohort Study

Aims: To assess the prevalence, 3-year course, and associated factors of temporomandibular joint (TMJ) pain in patients with newly diagnosed rheumatoid arthritis (RA). Methods: A total of 264 patients with newly diagnosed RA were included. Patients were assessed after 3 months, 6 months, 9 months, 1 year, 1.5 years, 2 years, and 3 years. TMJ pain was scored by manual palpation, and the prevalence of TMJ pain was calculated at baseline and at all seven follow-up intervals during 3 years. Factors assessed for a potential association with TMJ pain at baseline included: demographic factors (gender and age), disease-related factors (symptom duration, rheumatoid factor [RF], anti-cyclic citrullinated protein [anti-CCP], C-reactive protein [CRP], and Disease Activity Score 28 [DAS28]), and functional factors (Health Assessment Questionnaire [HAQ] and European Quality of Life 5 Dimensions Questionnaire [EQ5D]-anxiety/depression). A stepwise logistic regression model was used to determine factors associated with TMJ pain in patients with RA. Results: The prevalence of TMJ pain in patients with RA was 10.6% at baseline, which decreased to 3.6% in the first year after inclusion and remained stable thereafter. Disease activity as determined by the DAS28 was significantly associated with TMJ pain (odds ratio [OR] = 1.51; 95% confidence interval [95% CI] = 1.12-2.05; P = .009) at baseline. A second logistic regression analysis was performed with the following variables of the DAS28: erythrocyte sedimentation rate (ESR), tender joint count, swollen joint count, and global health. Tender joint count (OR = 1.06; 95% CI = 1.01-1.12; P = .03) and global health (OR = 1.02; 95% CI = 1.00-1.03; P = .03) were significantly associated with TMJ pain at baseline. The remaining factors included in the analysis were not significantly associated with TMJ pain at baseline. Conclusion: The prevalence of TMJ pain in patients with newly diagnosed RA is approximately 10% and decreases during follow-up, especially in the first year. Disease activity is a risk factor for TMJ pain in patients with newly diagnosed RA.